Methodology for Experimental Assessment of Electrical Loads in Urban Distribution Networks and Justification of Measurement Parameters

Abstract

Relevance: designing and modernising urban power supply systems requires reliable values of design loads. Such values cannot be obtained by theoretical modelling alone - they must be confirmed by field measurements. However, without a unified methodology and metrological support the results are not reproducible: if the measurement period, the sampling interval and the instrument class are chosen without justification, the daily maximum load is underestimated by 5–20 %. Therefore, developing a holistic methodology for organising experimental research within a project is an urgent task.

Aim: to develop a methodology for the experimental study of the electrical loads of urban distribution networks within the framework of the project, to organise the measurements, to statistically process the results and to assess their reliability.

Methods: theoretical analysis and the project approach, full-scale experiment, multi-point synchronous measurements, variation statistics, criteria for comparing variances, numerical experiments and metrological verification of the results.

Results: a five-stage project structure and a methodology for conducting the experiment were developed. Measurements at 24 facilities of a 0.4 kV distribution network in Tashkent showed that increasing the sampling interval from 1 s to 60 s underestimates the daily maximum load by 0.3–2.8 %; a 5 s interval and a 14-day measurement period provide a result with an error of 5 % at a confidence level of 95 %.